Answer:
ii. (5x – 6) (5x – 4)
= 5x(5x - 4) - 6(5x - 4)
= 25x^2 - 20x - 30x + 24
= 25x^2 - 50x + 24
iii. (8m – 3n) (8m + 6n)
= 8m(8m + 6n) - 3n(8m + 6n)
= 64m^2 + 48mn - 24mn - 18n^2
= 64m^2 - 18n^2
iv. (4a – 6) (4a + 6)
= 4a(4a + 6) - 6(4a + 6)
= 16a^2 + 24a - 24a - 36
= 16a^2 - 36
v. 98 × 102
= (100 - 2)(100 + 2)
= 10000 - 400
= 9600
vi. 104 × 103
= (100 + 4)(100 + 3)
= 10000 + 300 + 400 + 12
= 10,712
Explanation: